Fix issue participants (#13893)

* Fix issue participants

* use list class for margin

* remove wrapper and don't render on zero participants

* keep whitespace

* remove participants class

* add some margin for timetracking stuff

Co-authored-by: 6543 <6543@obermui.de>

web_src/less/_repository.less

@@ -1189,13 +1189,6 @@
       }
     }
 
-    .ui.participants {
-      img {
-        margin-top: 5px;
-        margin-right: 5px;
-      }
-    }
-
     .ui.depending {
       .item.is-closed {
         .title {